Trauma to the brain or spinal cord caused by physical forces acting on the skull or spinal column, by ischemic stroke, arrested breathing, cardiac arrest, Reye's syndrome, cerebral thrombosis, cerebral embolism, the neurological problems caused by AIDS, cerebral hemorrhage, encephalomyelitis, hydrocephalus, post-operative brain injury, cerebral infections, various concussions and elevated intracranial pressure results in edema and swelling of the affected tissues. This is followed by ischemia, hypoxia, necrosis, temporary or permanent brain and/or spinal cord injury and may result in death. The tissue mainly affected are classified as grey matter, more specifically astroglial cells. The specific therapy currently used for the treatment of the medical problems described include various kinds of diuretics (particularly osmotic diuretics), steroids (such as, 6-.alpha.-methylprednisolone succinate) and barbiturates. The usefulness of these agents is questionable and they are associated with a variety of untoward complications and side effects. Thus, the compounds of this invention comprise a novel and specific treatment of medical problems where no specific therapy is available.
Two recent publications, one entitled "Agents for the Treatment of Brain Injury" 1. (Aryloxy)alkanoic Acids, by Cragoe et al, J. Med. Chem., (1982) 25, 567-579 and the other, "Agents for the Treatment of Brain Edema" 2. [(2,3,9,9a-tetrahydro-3-oxo-9a-subtituted-1H-fluoren-7yl)oxy]alkanoic Acids and Their Analogs", by Cragoe et al, Med. Chem., 29, 825-841 (1986), report recent experimental testing of agents for treatment of brain injury and review the current status of treatment of brain injury. Additionally, U.S. Pat. Nos. 4,316,043, 4,317,922, 4,337,354, 4,356,313, 4,356,314, 4,389,417, 4,394,385, 4463,208, 4,465,850, 4,579,869, and 4,604,396 disclose certain alkanoic acids, cycloalkanoic acids or their amidine analogs for the treatment of grey matter edema.
The compounds of the invention have the added advantage of being devoid of the pharmacodynamic, toxic or various side effects characteristic of the diuretics, steroids and barbiturates.